Grandien A, Brás A, Martinez C
Centro Nacional de Biotecnologia, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
Scand J Immunol. 1996 Jan;43(1):47-55. doi: 10.1046/j.1365-3083.1996.d01-13.x.
Expression of CD40 on mouse cells was investigated comparing the binding to cells of a monoclonal antibody against CD40, to that of a soluble fusion protein consisting of the extracellular domains of the mouse CD40-ligand. The analysis of a series of established cell lines failed to demonstrate expression of CD40 on pro- or pre-B cells, and indicated that CD40 expression was restricted to cells that had undergone productive heavy- and light-chain gene rearrangements, and expressed surface Ig. In cells from normal mice, CD40 first becomes detectable, although at low levels, on a subset of small pre-B-II cells in bone marrow, the levels of CD40 expression increasing thereafter during B-cell maturation. Thus, immature B cells (IgM+ IgDlo B220lo) express intermediate levels of CD40, and mature B cells (IgM+ IgDhi B220hi) express high levels of CD40. Anatomical location also seems to correlate with the levels of CD40 expression, as B cells expressing the highest levels of CD40 were found in lymph nodes and Peyer's patches.
